1. Field of the Invention
The present invention relates generally to a printer apparatus for correcting a slant of a medium at a medium insertion port and, more particularly, to a printer apparatus for correcting slants of many kinds of mediums.
2. Description of the Related Art
A printer apparatus is used for executing a print on a medium such as a passbook, a check and a slip etc in, e.g., a financial institute etc. In this kind of printer apparatus, if the medium is inserted obliquely, the printing is effected obliquely. It is required that an operator should set the medium in a right position at the insertion port in order to prevent the slant of the medium.
When the operator implements this setting operation, however, the operator might be burdened with this operation. Such a printer apparatus is therefore provided with an automatic setting mechanism for correcting the slant of the medium. This automatic setting mechanism automatically corrects the slant of the medium after the operator has inserted the medium from the medium insertion port. This type of printer apparatus, it is desired, should stably correct the slant of the medium regardless of the thickness thereof.
FIG. 19 is an explanatory view showing the prior art.
As shown in FIG. 19, in the printer apparatus, the medium inserted from an insertion port 90 is conveyed by conveying rollers 92, 93. Then, a printing head 95 effects a print on the medium. After finishing the printing, the medium is returned to the insertion port 90.
A slant correcting roller 91 for correcting the slant of the medium is provided at the insertion port 90. This kind of slant correcting mechanism is disclosed in Japanese Patent Application Laid-Open Publication Nos.4-22657 and 2-23135. The slant correcting roller 91 makes the inserted medium impinge on an impingement member 94. This slant correcting roller 91 is constructed to stop the conveyance of the medium after the impingement of the medium. Therefore, the slant correcting roller 91 is constructed of polygonal rollers. The roller 91 is constructed of, e.g., a square roller.
A single piece of polygonal roller has hitherto been provided at the insertion port 90. Then, the one polygonal roller causes the medium to impinge upon the impingement member 94, thus correcting the slant thereof.
In the case of using a variety of mediums having different sizes, however, there arises a problem in which it is difficult to make the mediums of all the sizes impinge upon the impingement member.
Further, the printer apparatus deals with the mediums having a variety of thicknesses, i.e., a thick medium such as a passbook and a thin medium such as a slip. An impingement of the thick medium requires a comparatively large conveying force. If the impingement of the thin medium is caused by this conveying force, the thin medium might be bounced back after the thin medium has impinged upon the impingement member. This therefore presents a problem in which the slant of the thin medium is hard to correct.